Type refinement for SN 2005by

Avishay Gal-Yam, David Sand and Douglas Leonard report for the CCCP: We have observed SN 2005by (Park & Li, IAUC # 8523 ) with the DBSP spectrograph mounted on the 200" Hale Telescope at Palomar Observatory on June 4, 2005 UT. We find that this object, initially reported to be a type II SN (Modjaz et al., IAUC # 8523 ; Gal-Yam & Djorgovski, ATEL #480) can now be determined to be a type IIb SN, having developed prominent Helium lines, including those at 6678 and 7065 Angstrom.